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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-04-26 00:12:56 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-06-08 17:25:32 +0200 |
| commit | 820687a7b98a5031207893ff265f97c0a0ad403e (patch) | |
| tree | 7ca7ed37ea08413a9e36951ccbd50685ea55da20 | |
| parent | srcu-cbmc: Use /usr/bin/awk instead of /bin/awk (diff) | |
| download | linux-820687a7b98a5031207893ff265f97c0a0ad403e.tar.xz linux-820687a7b98a5031207893ff265f97c0a0ad403e.zip | |
rcuperf: Add writer_holdoff boot parameter
This commit adds a writer_holdoff boot parameter to rcuperf, which is
intended to be used to test Tree SRCU's auto-expediting. This
boot parameter is in microseconds, and defaults to zero (that is,
disabled). Set it to a bit larger than srcutree.exp_holdoff,
keeping the nanosecond/microsecond conversion, to force Tree SRCU
to auto-expedite more aggressively.
This commit also adds documentation for this parameter, and fixes some
alphabetization while in the neighborhood.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 11 | ||||
| -rw-r--r-- | kernel/rcu/rcuperf.c | 3 |
2 files changed, 11 insertions, 3 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 3598464ca8ed..01b5ab92d251 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3357,17 +3357,22 @@ rcuperf.perf_runnable= [BOOT] Start rcuperf running at boot time. + rcuperf.perf_type= [KNL] + Specify the RCU implementation to test. + rcuperf.shutdown= [KNL] Shut the system down after performance tests complete. This is useful for hands-off automated testing. - rcuperf.perf_type= [KNL] - Specify the RCU implementation to test. - rcuperf.verbose= [KNL] Enable additional printk() statements. + rcuperf.writer_holdoff= [KNL] + Write-side holdoff between grace periods, + in microseconds. The default of zero says + no holdoff. + rcutorture.cbflood_inter_holdoff= [KNL] Set holdoff time (jiffies) between successive callback-flood tests. diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c index 49c8ed6bd2fd..d80f11d9f8bd 100644 --- a/kernel/rcu/rcuperf.c +++ b/kernel/rcu/rcuperf.c @@ -68,6 +68,7 @@ torture_param(int, nwriters, -1, "Number of RCU updater threads"); torture_param(bool, shutdown, !IS_ENABLED(MODULE), "Shutdown at end of performance tests."); torture_param(bool, verbose, true, "Enable verbose debugging printk()s"); +torture_param(int, writer_holdoff, 0, "Holdoff (us) between GPs, zero to disable"); static char *perf_type = "rcu"; module_param(perf_type, charp, 0444); @@ -447,6 +448,8 @@ rcu_perf_writer(void *arg) } do { + if (writer_holdoff) + udelay(writer_holdoff); wdp = &wdpp[i]; *wdp = ktime_get_mono_fast_ns(); if (gp_async) { |